Is it permissible for my wife to request separate accommodation due to her annoyance with the frequent visits of my siblings and their spouses, even though I have been living with my mother on the same floor since my marriage?

The wife has the right to a suitable independent dwelling, meaning a separate part of a house with its facilities. If your wife has an independent dwelling, she has no right to demand another one unless there is harm. The husband should combine honoring his parents with treating his wife kindly.